/* eslint-disable */
import XLSX from "xlsx";

function auto_width(ws, data) {
	/*set worksheet max width per col*/
	const colWidth = data.map(row =>
		row.map(val => {
			/*if null/undefined*/
			if (val == null) {
				return { wch: 10 };
			} else if (val.toString().charCodeAt(0) > 255) {
				/*if chinese*/
				return { wch: val.toString().length * 2 };
			} else {
				return { wch: val.toString().length };
			}
		})
	);
	/*start in the first row*/
	let result = colWidth[0];
	for (let i = 1; i < colWidth.length; i++) {
		for (let j = 0; j < colWidth[i].length; j++) {
			if (result[j]["wch"] < colWidth[i][j]["wch"]) {
				result[j]["wch"] = colWidth[i][j]["wch"];
			}
		}
	}
	ws["!cols"] = result;
}

function json_to_array(key, jsonData) {
	return jsonData.map(v =>
		key.map(j => {
			return v[j];
		})
	);
}

// fix data,return string
function fixdata(data) {
	let o = "";
	let l = 0;
	const w = 10240;
	for (; l < data.byteLength / w; ++l) o += String.fromCharCode.apply(null, new Uint8Array(data.slice(l * w, l * w + w)));
	o += String.fromCharCode.apply(null, new Uint8Array(data.slice(l * w)));
	return o;
}

// get head from excel file,return array
function get_header_row(sheet) {
	const headers = [];
	const range = XLSX.utils.decode_range(sheet["!ref"]);
	let C;
	const R = range.s.r; /* start in the first row */
	for (C = range.s.c; C <= range.e.c; ++C) {
		/* walk every column in the range */
		var cell = sheet[XLSX.utils.encode_cell({ c: C, r: R })]; /* find the cell in the first row */
		var hdr = "UNKNOWN " + C; // <-- replace with your desired default
		if (cell && cell.t) hdr = XLSX.utils.format_cell(cell);
		headers.push(hdr);
	}
	return headers;
}

export const export_table_to_excel = (id, filename) => {
	const table = document.getElementById(id);
	const wb = XLSX.utils.table_to_book(table);
	XLSX.writeFile(wb, filename);

	/* the second way */
	// const table = document.getElementById(id);
	// const wb = XLSX.utils.book_new();
	// const ws = XLSX.utils.table_to_sheet(table);
	// XLSX.utils.book_append_sheet(wb, ws, filename);
	// XLSX.writeFile(wb, filename);
};

export const export_json_to_excel = ({ data, key, title, filename, autoWidth }) => {
	const wb = XLSX.utils.book_new();
	data.unshift(title);
	const ws = XLSX.utils.json_to_sheet(data, { header: key, skipHeader: true });
	if (autoWidth) {
		const arr = json_to_array(key, data);
		auto_width(ws, arr);
	}
	XLSX.utils.book_append_sheet(wb, ws, filename);
	XLSX.writeFile(wb, filename + ".xlsx");
};

export const export_array_to_excel = ({ key, data, title, filename, autoWidth }) => {
	const wb = XLSX.utils.book_new();
	const arr = json_to_array(key, data);
	arr.unshift(title);
	const ws = XLSX.utils.aoa_to_sheet(arr);
	if (autoWidth) {
		auto_width(ws, arr);
	}
	XLSX.utils.book_append_sheet(wb, ws, filename);
	XLSX.writeFile(wb, filename + ".xlsx");
};

export const read = (data, type) => {
	/* if type == 'base64' must fix data first */
	// const fixedData = fixdata(data)
	// const workbook = XLSX.read(btoa(fixedData), { type: 'base64' })
	const workbook = XLSX.read(data, { type: type });
	const firstSheetName = workbook.SheetNames[0];
	const worksheet = workbook.Sheets[firstSheetName];
	const header = get_header_row(worksheet);
	const results = XLSX.utils.sheet_to_json(worksheet);
	return { header, results };
};

export default {
	export_table_to_excel,
	export_array_to_excel,
	export_json_to_excel,
	read,
};
